/*************************************************************************
	> File Name: 1.epoll.c
	> Author: 
	> Mail: 
	> Created Time: Tue 02 Mar 2021 07:15:06 PM CST
 ************************************************************************/
#define MAX_EVENTS 10
struct epoll_event ev, events[MAX_EVENTS];
int listen_sock, conn_sock, nfds, epollfd;

/* Code to set up listening socket, 'listen_sock',
  (socket(), bind(), listen()) omitted */

epollfd = epoll_create1(0);
if (epollfd == -1) {
   perror("epoll_create1");
   exit(EXIT_FAILURE);
}

ev.events = EPOLLIN;
ev.data.fd = listen_sock;
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, listen_sock, &ev) == -1) {
   perror("epoll_ctl: listen_sock");
   exit(EXIT_FAILURE);
}

for (;;) {
   nfds = epoll_wait(epollfd, events, MAX_EVENTS, -1);
   if (nfds == -1) {
       perror("epoll_wait");
       exit(EXIT_FAILURE);
   }

   for (n = 0; n < nfds; ++n) {
       if (events[n].data.fd == listen_sock) {
           conn_sock = accept(listen_sock,
                              (struct sockaddr *) &addr, &addrlen);
           if (conn_sock == -1) {
               perror("accept");
               exit(EXIT_FAILURE);
           }
           setnonblocking(conn_sock);
           ev.events = EPOLLIN | EPOLLET;
           ev.data.fd = conn_sock;
           if (epoll_ctl(epollfd, EPOLL_CTL_ADD, conn_sock,
                       &ev) == -1) {
               perror("epoll_ctl: conn_sock");
               exit(EXIT_FAILURE);
           }
       } else {
           do_use_fd(events[n].data.fd);
       }
   }
}
